For students of TV hitmaking, no franchise is more fascinating than the one that began with "Law & Order." The original lasted two decades in prime time and should achieve immortality in reruns. For now, three domestic "L&O" spinoffs also are on the air. How many times must creator and executive producer Dick Wolf have been asked: What is the secret recipe for success? As "Law & Order: LA" came back to television this month after a hiatus and revamp, an answer suggested itself: Magic formula? Who knows?

When it began last autumn, the Los Angeles "L&O" not only left its siblings by leaving New York. It also ditched the franchise's iconic opening and sound effects, switching to trendy music and introducing younger-generation star Skeet Ulrich as a detective (alongside the more substantial babe magnet Corey Stoll). Alfred Molina alternated with Terrence Howard as the weekly prosecutor.

It isn't clear why this arrangement—which had respectable ratings and youth appeal—came to a screeching halt. But when the series returned April 11, little was new or improved. The distinctive "L&O" bonging ta-da sound had been added, as had the familiar character of Deputy District Attorney Connie Rubirosa (Alana De La Garza), last seen back on the original "Law & Order." Minor tweaks, it would seem, to a series that had been fun enough as it was.

Then things got weird. In the first episode this month, Mr. Ulrich's detective character was killed so that he could be replaced, dramatically speaking, by Mr. Molina. Would or could a long-time prosecutor ever quit to become a detective again? That contortion did leave the likeable Mr. Howard as the show's main prosecutor. Yet because Mr. Howard is not a commanding presence here, "Law & Order: LA" is on track to become the Alfred Molina show.

Who could complain? Mr. Molina is a great, great actor. But precisely because he is so riveting, when he's called upon to recite a routine line like, "Did you notice anything about his body?" it can be distracting and even sound silly. It's as if Mr. Molina's acting chops make him too big for the small screen. Cast as the chief pontificator, he looms over the show like a mastodon. In fact, the entire cops-prosecutor dynamic is different here. Back in NYC, the police and lawyers kept at a distance, almost across a class barrier. In "LA," the cops often seem to run the show.

There's no reason why a new series can't go in a new direction. The original "L&O" struck gold by not wasting time on the private lives of society's protectors. Then spin-off "SVU" delved into its detective's personal lives, and thrived. The move from New York and from a pool of stage actors to screen ones, was bound to change things. But changes, including the setting, can be effective. This week, for instance, the story was inspired by the 2010 murder of movie publicist Ronni Chasen.

What "LA" does not have so far, though, is the finely tuned writing and dramatic moral dimensions that made the original so distinctive. "L&O" excelled by portraying decent folks trying to make moral choices in a world where the right thing was not always clear, or possible. So far, the Los Angeles version is neither subtle nor nuanced. Instead, what we get are omnidimensional blunt forces exemplified by Peter Coyote in a (scenery chewing) role as the callow and cynical D.A. Jerry Hardin. He's not politically conflicted like his franchise predecessors—he seems mean, and sinister. When he sneers like a pervert it's spell-breaking all right, but not in a good way.